Hot alkali‐extracted antioxidative crude polysaccharide from a novel mushroom enhances immune response via TLR‐mediated NF‐κB activation: A strategy for full utilization of a neglected tribal food

Abstract

Mushroom polysaccharides have been revered for decades as incredibly versatile compounds suitable for application in biomedical, pharmaceutical, food, and cosmetic industries. In that essence Russula alatoreticula, a traditionally appraised unique macrofungus, has earlier been explored to contain functional macromolecules elicited by hydrothermal and cold alkali systems. Remnants of that multistep extraction could further be utilized not only to isolate high-value components, but also to reduce waste material. With this in mind, we decided to recycle leftover residue of the tribal delicacy, rather than undervalue, by following heated NaOH reflux. Intriguingly, the effort resulted productive isolation of carbohydrate fraction (RualaHap) enriched in β-glucan that showed excellent antioxidant activity in terms of radical scavenging, chelating ability, and reducing power with EC 50 of 207-5000 μg/ml. Besides strong immune boosting prowess was also witnessed as exposure of RAW 264.7 cells to the metabolites influenced macrophage viability and phagocytosis in a time-dependent manner. Induction of intracellular NO and ROS generation was also enumerated along with aggrandized production of pseudopods representing hallmark of monocyte stimulation. Moreover, the treatment drastically triggered level of TLR-2, TLR-4, NF-κB, Iκ-Bα, iNOS, COX-2, TNF-α, IFN-γ, and IL-10 maintaining balance between M1 and M2 cytokines via TLR coordinated NF-κB pathway. Conclusively the research offers a roadmap for better utilization of a species boasted in traditional practice aiding future implementation of RualaHap as ingredients of nutraceuticals or functional foods. Practical applications At present, macrofungal polysaccharides are regarded as an ideal resource for a range of safe uses encompassing direct contact or ingestion by human. In this context, RualaHap isolated from the wild edible mushroom, R. alatoreticula, could have a broad application prospect, particularly in development of natural therapeutics to ameliorate radical-induced ailment and immune-deficiency condition. The biopolymers could thus be utilized in functional diet or complementary medicine to improve health that in turn might raise local cost of the abandoned taxon boosting rural empowerment.

Immunity boosting nutraceuticals: Current trends and challenges

“…The β‐glucan‐enriched fraction of the macrofungus enhanced macrophage activity. This was observed by an increase in engulfment power, NO synthesis, and ROS production (Khatua et al., 2021). Murphy et al.…”

Immune-enhancing effect of water-soluble beta-glucan derived from enzymatic hydrolysis of yeast glucan

“…2 F). Most importantly, the attacked macrophages displayed dendritic contours with microvilli-like structures across their entire surface, indicating definite signs of their immune-boosting ability [ 18 ]. These morphological changes suggest that WSY glucan could induce macrophage activity.…”

Mushrooms as Functional and Nutritious Food Ingredients for Multiple Applications

“…Mushrooms contain both 1,4/1,4-6-α-glucans and 1,3/1,6-β-glucans . β-Glucans from mushrooms have been extracted by common methods such as hot water extraction or alkaline deproteinization followed by ethanol precipitation and purification. − So far, novel extraction of mushroom β-glucans includes ultrasonic-assisted extraction (UAE) applied to mushroom wastes, , supercritical-CO 2 extraction on Indian oyster ( Pleurotus pulnomarius ) and Ganoderma lucidum , , and microwave-assisted extraction on Agaricus blazei and Inonotus obliquus . Enhanced antioxidant activities have been observed in UAE, and the technique has been shown to be more effective and time efficient compared to simple water extraction.…”